SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56b2b023e51eec3f9302e226ef69cb9b542427da15e3c04485de62315a991a2a' 
  AND token = 'oqFSEEuD0QWjw4WQfdYKuSjXiNnfZ/zOix9zBjCHxZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}